Progress In Perovskite Solar Cells Research Articles

Opportunities of copper addition in CH3NH3PbI3 perovskite and their photovoltaic performance evaluation

Perovskite solar cells (PSCs) have encountered a fulgurant development in their power-conversion efficiency (PCEs) generation in the drive to provide a facile, cheap and clean source of energy over just a few years. The most efficient PSCs are fabricated using CH3NH3PbI3 (MAPbI3) perovskite. However, being a promising photovoltaic (PV) performance piloted by MAPbI3, Pb-toxicity and poor stability obstructs the progress of PSCs in PV technology. In this regard, replacing Pb with some environmentally friendly, cheaper, and similar optoelectronic behaviour related alternative material or element is highly desirable. In this work, an attempt was made on copper as Cu (I) addition in the perovskite, MAPbI3 through some exotic ways in an intention of Pb replacement, i.e., complete Pb replacement with Cu, which generates MACuxI3 (1 ≤ x ≥ 2); partial lead replacement, i.e., MAPb1−xCuxI3; and cocktail perovskite, i.e., both MAPbI3 and MACuxI3 mixture, and finally they are employed for carbon-based perovskite solar cells. Remarkably, Cu incorporation facilitates the near-infrared (NIR) absorption, indicating a maximum solar spectrum absorbance. Integration of Cu as MAPb1−xCuxI3 results in the maximum PCE of ~12.85%, whereas using 1:1 cocktail perovskite solution of MAPbI3 and MACuxI3 exhibits an average PCE of ~12.43%. On the other hand, during complete Pb substituted perovskites, MACuxI3, the device has only experienced an average PCE of ~4.0%. However, MACuxI3-based PSCs lead to negligible PCE degradation as perceived up to 1000 h, whereas Pb-based other devices are experienced rapid PCE depletion over the same period. Noticeably, Cu-incorporation facilitates a comparatively steeper and lesser PCE degradation rate than Pb-based PSCs. These results may help exploit unlimited possibilities of the potential application of Pb-free based highly stable solar cells and highlights the opportunities for broad solar absorption towards the NIR route and enhanced device stability. Besides, Cu employment has the advantages of environmentally benign impact, earth abundance, good thermal and aqueous stability.

Research progress of nanoarray structure transport layers in perovskite solar cells

The electron/hole transport layer can promote charge transfer and improve device performance, which is used in perovskite solar cells. The nanoarray structure transport layers can not only further promote carrier transport but also reduce recombination. It also has a great potential in enhancing perovskite light absorption, improving device stability and inhibiting the crack nucleation of different structure layers in perovskite solar cells. This paper reviewed the research progress of perovskite solar cells with different nanoarray structure transport layers. The challenges and development directions of perovskite solar cells based on nanoarray structure transport layers are also summarized and prospected.

Performance analysis of highly efficient 2D/3D bilayer inverted perovskite solar cells

Photovoltaic conversion efficiency (PCE) acquired in perovskite solar cells (PSCs) is currently competitive with that of other commercial solar cells. Despite profound progress in PSCs in the last few years, achieving long term stability is considered as a prime hindrance for the commercialization of these solar cells. Recently, low dimensional perovskites have drawn extensive interests in research to improve photo-stability, however, wide bandgap limits output power of low dimensional perovskite-based solar cells. Two-dimensional/three-dimensional (2D/3D) bilayer PSCs can overcome this barrier via innovation in device engineering that can retain high performance and long-term photostability simultaneously. For example, inverted p-i-n structure of 2D/3D bilayer PSCs has drawn enormous interests in recent years due to cost-effectiveness, low temperature processing, and inhibited hysteresis characteristics. In this report, we present a numerical modeling approach to optimize the performance of an inverted 2D/3D bilayer PSC with a novel device architecture: ITO/NiOx/BA2MAn-1PbnI3n+1/MAPbI3/ZnO/Al. Perovskite materials with thickness of ∼900 nm (BA2MAn-1PbnI3n+1(200 nm)/MAPbI3 (700 nm)) and defect density of 2 × 1014 cm−3 yields best cell efficiency, that is up to ∼24.75%. Further optimization of electron transport layer and hole transport layer along with their donor and acceptor density level leads to 2.56% increase in the efficiency, that is from ∼23.53% to ∼24.75%. Our estimation suggests that incorporating 2D BA2MAn-1PbnI3n+1 perovskite into 3D MAPbI3 perovskite yield high throughput and simultaneously minimize the fabrication cost for active absorber layer in inverted PSCs.

Synthesis of porous electrode from CH3NH3PbBr3 single crystal for efficient supercapacitor application: Role of morphology on the charge storage and stability

Metal halide perovskites (MHPs) are the most exciting class of next generation energy storage materials owing to their high ionic as well as electronic conductivity. There has been tremendous progress in perovskite solar cells as well as perovskite light emitting diodes in last decade, however the use of halide perovskites is limited in energy storage application. Moreover, the device performance of MHP based supercapacitors is still inferior due to the lack of fundamental understanding of charge storage in perovskite supercapacitor. Here, we have fabricated methylammonium lead tri-bromide perovskite-based electrode by spin-coating as well as from the single crystal for electrolyte-based supercapacitors and demonstrated that the device performance strongly dependent on the electrode morphology. Our experimental results show that the modified electrode from the MHP single crystal has 500-time higher volumetric capacitance (∼ 429.1 F cm−3 @ 5 mV s−1) compared to the spin-coated thin-film based capacitors (∼ 0.8 F cm−3 @ 5 mV s−1) having same electrolyte and device structure. The modified electrode exhibits much higher ionic diffusion coefficient of 5.61 × 10−13 m2 s−1, and a very low charge transfer resistance (CTR) of ∼ 62.5 Ω cm−2 compared to thin film-based electrodes (Dion = 1.41 × 10−16 m2 s−1, CTR ∼ 4.4 kΩ cm−2) due to highly porous isotropic structure with high degree of micro-strain. Moreover, MHPs based supercapacitor exhibits a very quick energy deliver response time of 5 – 13 ms. We have got energy density ∼12.75 W h kg–1 at a power density of ∼225 W kg–1 which shows significant improvement in metal halide perovskite-based energy storage devices. We have found that the major contribution in powder electrode-based capacitor is diffusion limited capacitance while thin-film based devices show mainly electric double layer capacitance. Our modified powder electrode-based supercapacitors show significant improvement in terms of cyclic stability over 97% as well as coulombic efficiency over 91% after 1500 cycles of operation.

Sandwiched electrode buffer for efficient and stable perovskite solar cells with dual back surface fields

<h2>Summary</h2> With the rapid progress of perovskite solar cells (PSCs), both high efficiency and sufficient stability are required simultaneously for their real-life application, wherein interfaces play an essential role. In this work, we develop sandwiched electrode buffer (SEB) with respect to the hole-transport layer (HTL), wherein dual back surface fields are implemented at two interfaces in relevance. The SEB bridges the absorber to the back electrode with the desired band alignment and multi-defect passivation effects, which stabilize the perovskite, HTL, and metal electrodes. Accordingly, planar n-i-p PSCs with SEB achieve an efficiency of 23.9% (certified 23.4%). Notably, they exhibit a remarkable operational stability with only a 3% efficiency decline for 2,000 h maximum power point tracking under 1-Sun illumination. Furthermore, the devices also show excellent thermal stability and humidity stability. Therefore, the SEB configuration boosts both efficiency and stability of PSCs, which paves the way for the commercialization of perovskite optoelectronics.

A short report on up to date Stability progress of Perovskite solar cells

A short report on up to date Stability progress of Perovskite solar cells

A brief review of hole transporting materials commonly used in perovskite solar cells

Perovskite solar cells (PSCs) have been brought into sharp focus in the photovoltaic field due to their excellent performance in recent years. The power conversion efficiency (PCE) has reached to be 25.2% in state-of-the-art PSCs due to the outstanding intrinsic properties of perovskite materials as well as progressive optimization of each functional layer, especially the active layer and hole transporting layer (HTL). In this review, we mainly discuss various hole transporting materials (HTMs) consisting of HTL in PSCs. The progress in PSCs is firstly introduced, then the roles of HTL playing in photovoltaic performance improvement of PSCs are emphasized. Finally, we generally categorize HTMs into organic and inorganic groups and demonstrate both their advantages and disadvantages. Specially, we introduce several typical organic HTMs such as P3HT, PTTA, PEDOT:PSS, spiro-OMeTAD, and inorganic HTMs such as copper-based materials (CuOx, CuSCN, CuI, etc.), nickel-based materials (NiOx), and two-dimensional layered materials (MoS2, WS2, etc.). On basis of reviewing the reported HTMs in recent years, we expect to provide some enlightenment for design and application of novel HTMs that can be used to further promote PSCs performance.

Perovskite Solar Cells for Space Applications: Progress and Challenges.

Metal halide perovskites have aroused burgeoning interest in the field of photovoltaics owing to their versatile optoelectronic properties. The outstanding power conversion efficiency, high specific power (i.e., power to weight ratio), compatibility with flexible substrates, and excellent radiation resistance of perovskite solar cells (PSCs) enable them to be a promising candidate for next-generation space photovoltaic technology. Nevertheless, compared with other practical space photovoltaics, such as silicon and III-V multi-junction compound solar cells, the research on PSCs for space applications is just in the infancy stage. Therefore, there are considerable interests in further strengthening relevant research from the perspective of both mechanism and technology. Consequently, the approaches used for and the consequences of PSCs for space applications are reviewed. This review provides an overview of recent progress in PSCs for space applications in terms of performance evolution and mechanism exploration of perovskite films and devices under space extreme environments.

Lead-free tin perovskite solar cells

Summary The development of efficient and stable lead-free perovskite solar cells (PSCs) is crucial for addressing the concern of environmental pollution from the toxic element lead. In recent years, tin PSCs have emerged as a promising candidate for high-performance, eco-friendly photovoltaic technology with a high certified power conversion efficiency (PCE) of more than 11%, indicating a great potential for future applications. Here, we review the recent efficiency progress of tin PSCs based on the equivalent circuit model of solar cells. We then discuss approaches toward efficiency improvement from the device viewpoint, such as optimizing the band gap, increasing the light-harvesting efficiency and carrier diffusion length, surface passivation, and regulating the interface energy-level alignment. Finally, we point out the possibility of reaching 20% PCE for tin PSCs and issues regarding enlarging the cell size and realizing scalable production in the future. We expect that these perspectives will be helpful for accelerating the commercialization of tin PSCs.

Strain in perovskite solar cells: origins, impacts and regulation.

Metal halide perovskite solar cells (PSCs) have seen an extremely rapid rise in power conversion efficiencies in the past few years. However, the commercialization of this class of emerging materials still faces serious challenges, one of which is the instability against external stimuli such as moisture, heat and irradiation. Much focus has deservedly been placed on understanding the different origins of intrinsic instability and thereby enhancing their stability. Among these, tensile strain in perovskite films is an important source of instability that cannot be overcome using conventionally extrinsic stabilization approaches such as encapsulation. Here we review recent progress in the understanding of the origin of strain in perovskites as well as its corresponding characterization methods, and their impacts on the physical properties of perovskites and the performance of PSCs including efficiency and stability. We then summarize the latest advances in strain-regulation strategies that improve the intrinsic stability of perovskites and photovoltaic devices. Finally, we provide a perspective on how to make further progress in stable and high-efficiency PSCs via strain engineering.

Enhanced electrical properties of Li-salts doped mesoporous TiO2 in perovskite solar cells

<h2>Summary</h2> The charge transferability of the electron transfer layers (ETLs) is important for achieving high performance in mesoscopic (mp) perovskite solar cells (PSCs). However, because of the low electron extraction efficiency of TiO₂, lithium doping is essentially required. In this work, we compared the electrical properties of mp-TiO₂ doped with Li-salts with different anions—LiTFSI, Li₂CO₃, LiCl, and LiF. Interestingly, we found that the anions of the Li-salt dopants affect the electrical properties of the ETLs and the solar cell performance. The Li₂CO₃ doping of mp-TiO₂ led to conduction bands deeper than those of pristine mp-TiO₂ or other doped mp-TiO₂. The maximum efficiency of 25.28% and certified efficiency of 24.68% (Newport) was obtained by using Li₂CO₃ dopant. This optimization of the ETLs properties is expected to greatly contribute to the progress of PSCs by leading to further increases in their efficiency.

Long-Term Stability Analysis of 3D and 2D/3D Hybrid Perovskite Solar Cells Using Electrochemical Impedance Spectroscopy.

Despite the remarkable progress in perovskite solar cells (PSCs), their instability and rapid degradation over time still restrict their commercialization. A 2D capping layer has been proved to overcome the stability issues; however, an in-depth understanding of the complex degradation processes over a prolonged time at PSC interfaces is crucial for improving their stability. In the current work, we investigated the stability of a triple cation 3D ([(FA0.83MA0.17)Cs0.05]Pb(I0.83Br0.17)3) and 2D/3D PSC fabricated by a layer-by-layer deposition technique (PEAI-based 2D layer over triple cation 3D perovskite) using a state-of-art characterization technique: electrochemical impedance spectroscopy (EIS). A long-term stability test over 24 months was performed on the 3D and 2D/3D PSCs with an initial PCE of 18.87% and 20.21%, respectively, to suggest a more practical scenario. The current-voltage (J-V) and EIS results showed degradation in both the solar cell types; however, a slower degradation rate was observed in 2D/3D PSCs. Finally, the quantitative analysis of the key EIS parameters affected by the degradation in 3D and 2D/3D PSCs were discussed.

Recent Progress and Challenges of Electron Transport Layers in Organic–Inorganic Perovskite Solar Cells

Organic–inorganic perovskites are crystalline light absorbers which are gaining great attraction from the photovoltaic community. Surprisingly, the power conversion efficiencies of these perovskite solar cells have rapidly increased by over 25% in 2019, which is comparable to silicon solar cells. Despite the many advances in efficiency, there are still many areas to be improved to increase the efficiency and stability of commercialization. For commercialization and enhancement of applicability, the development of electron transport layer (ETL) and its interface for low temperature processes and efficient charge transfer are very important. In particular, understanding the ETL and its interface is of utmost importance, and when this understanding has been made enough, excellent research results have been published that can improve the efficiency and stability of the device. Here, we review the progress of perovskite solar cells. Especially we discuss recent important development of perovskite deposition method and its engineering as well as the electron transport layer.

2D metal-organic framework for stable perovskite solar cells with minimized lead leakage.

Despite the notable progress in perovskite solar cells, maintaining long-term operational stability and minimizing potentially leaked lead (Pb2+) ions are two challenges that are yet to be resolved. Here we address these issues using a thiol-functionalized 2D conjugated metal-organic framework as an electron-extraction layer at the perovskite/cathode interface. The resultant devices exhibit high power conversion efficiency (22.02%) along with a substantially improved long-term operational stability. The perovskite solar cell modified with a metal-organic framework could retain more than 90% of its initial efficiency under accelerated testing conditions, that is continuous light irradiation at maximum power point tracking for 1,000 h at 85 °C. More importantly, the functionalized metal-organic framework could capture most of the Pb2+ leaked from the degraded perovskite solar cells by forming water-insoluble solids. Therefore, this method that simultaneously tackles the operational stability and lead contamination issues in perovskite solar cells could greatly improve the feasibility of large-scale deployment of perovskite photovoltaic technology.

Changes in the Electrical Characteristics of Perovskite Solar Cells with Aging Time.

The last decade has witnessed the impressive progress of perovskite solar cells (PSCs), with power conversion efficiency exceeding 25%. Nevertheless, the unsatisfactory device stability and current–voltage hysteresis normally observed with most PSCs under operational conditions are bottlenecks that hamper their further commercialization. Understanding the electrical characteristics of the device during the aging process is important for the design and development of effective strategies for the fabrication of stable PSCs. Herein, electrochemical impedance spectroscopical (IS) analyses are used to study the time-dependent electrical characteristics of PSC. We demonstrate that both the dark and light ideality factors are sensitive to aging time, indicating the dominant existence of trap-assisted recombination in the investigated device. By analyzing the capacitance versus frequency responses, we show that the low-frequency capacitance increases with increasing aging time due to the accumulation of charges or ions at the interfaces. These results are correlated with the observed hysteresis during the current–voltage measurement and provide an in-depth understanding of the degradation mechanism of PSCs with aging time.

Inorganic Halide Perovskite Solar Cells: Progress and Challenges

AbstractAll‐inorganic perovskite semiconductors have recently drawn increasing attention owing to their outstanding thermal stability. Although all‐inorganic perovskite solar cells (PSCs) have achieved significant progress in recent years, they still fall behind their prototype organic–inorganic counterparts owing to severe energy losses. Therefore, there is considerable interest in further improving the performance of all‐inorganic PSCs by synergic optimization of perovskite films and device interfaces. This review article provides an overview of recent progress in inorganic PSCs in terms of lead‐based and lead‐free composition. The physical properties of all‐inorganic perovskite semiconductors as well as the hole/electron transporting materials are discussed to unveil the important role of composition engineering and interface modification. Finally, a discussion of the prospects and challenges for all‐inorganic PSCs in the near future is presented.

Recent advances in interface engineering of all-inorganic perovskite solar cells.

All-inorganic perovskite solar cells (PSCs) have become one of the most attractive research fields in recent years due to their excellent thermal stability and light stability as compared with their organic-inorganic hybrid counterparts. However, there is still a long way to go for their commercial application due to their low efficiency and poor stability under humidity conditions. Herein, an overview of the recent progress of all-inorganic PSCs based on interface engineering is provided. The main roles of interface engineering, adjusting energy-level alignment, enhancing charge transport capacity, passivating interface defects, modulating morphology of perovskite films, stabilizing perovskite phase, broadening spectral absorption, eliminating electrical hysteresis and enhancing operational stability, are summarized with examples, which paves the way for highly efficient and stable all-inorganic PSCs. Some of the latest progress in incorporating dopants to charge transport materials and modifying interface properties in all-inorganic PSCs are also covered.

Research progress in lead-less or lead-free three-dimensional perovskite absorber materials for solar cells

The trend toward lead-free or lead-less perovskite solar cells (PSCs) has attracted increasing attention over the past few years because the toxicity of lead (Pb) is one of the substantial restrictions for large-scale applications. Researchers have investigated the viability of substituting Pb with other elements (group 14 elements, group 2 elements, transition-metal elements, and group 13 and 15 elements) in the three-dimensional (3D) perovskites by theoretical calculations and experimental explorations. In this paper, recent research progress in Pb-less and Pb-free PSCs on the perovskite compositions, deposition methods, and device structures are summarized and the main problems that hinder the enhancement of device efficiency and stability are discussed in detail. To date, the fully Sn-based PSCs have shown a power conversion efficiency (PCE) of 8.12% and poor device stability. However, lead-less PSCs have shown higher PCE and a better stability. In addition, the introduction of double-perovskite materials also draws researchers’ attention. We believe that the engineering of elemental composition, perovskite deposition methods, and interfacial modification are critical for the future development of Pb-less and Pb-free PSCs.

Low-Temperature Annealed Perovskite Films: A Trade-Off between Fast and Retarded Crystallization via Solvent Engineering.

Currently, in the field of photovoltaics, researchers are working hard to produce efficient, stable, and commercially feasible devices. The prime objective behind the innovation of any photovoltaic device is to yield more energy with easy manufacture and less process cost. Perovskite solar cells (PSCs) are prominent in the field of photovoltaics, owing to its low material cost, simple fabrication process, and ideal optoelectronic properties. Despite rapid augmentation in progress of PSCs, it is still a bottleneck to produce a high-quality perovskite layer at low temperatures in a short time. Herein, a facile solvent engineering technique is used to produce a high-quality perovskite layer at 50 °C in just 30 min. We employed solvent coordination strength to form the intermediate state as well as their sensitive behavior against antisolvent to establish a trade-off between fast and retarded crystallization. Dimethylsulphoxide (DMSO), a traditional co-solvent is used as an additive instead of co-solvent; in contrast, mixed 1-methyl-2-pyrrolidinone (NMP) and dimethylacetamide are employed as principal solvents for perovskite precursors. Different volume ratios of DMSO as a fraction of NMP are added to examine the evolution of the perovskite layer at low temperatures. It is noted that the mixed solvent with 30% DMSO shows a pin-hole free, uniform, and compact layer with a strong absorption spectrum. Promisingly, the corresponding device with 30% DMSO shows a high efficiency of 18.19%, which is even comparable to traditionally high-temperature annealed PSCs. These findings may provide a way to produce low-temperature annealed, high-quality perovskite films and subsequently facilitate the production of cost-effective and efficient devices.

Ab-initio calculation of APbI3 (A=Li, Na, K, Rb and Cs) perovskite crystal and their lattice constants optimization using density functional theory

Halide perovskite materials APbI3 (with A is inorganic alkaline cation) have received many attentions in some recent years related to the rapid progress of perovskite solar cells. Particularly, CsPbI3 perovskite has been much investigated due to relatively more stable in comparison to other inorganic cation while its energy conversion efficiency has reached 10.5%. In this study, we report our calculation results of the geometric structure and the electronic structure of these inorganic perovskites with various alkaline cation. The calculations were performed by employing the Density Functional Theory (DFT) method using Quantum Espresso computational software package. The calculation employed variable-cell relaxation algorithm (vc-relax) to obtain the lowest total energy value and the corresponding Density of States (DOS). In addition, Ultrasoft pseudopotentials and PBE exchange-correlation functions were used. The cut-off of kinetic energy was set at 40 Rydberg and the k-point was set at 5x5x5. The computation results lead to the energy gap range in 1.40 eV to 1.46 eV. In addition, there is also an agreement between the electronic band structures and the DOS distribution pattern for optimum lattice constant.